[mamachan]

No, the "downgrade reso" feature is not in spmc 16, only in the abandonned spmc 17 alpha and coming in mrmc
What is seen is just the global resolution in action, I guess

I'm not an expert and I do not know what exactly happens.

But if i set Shield al 2160p 60Hz and SPMC at 1080p 30Hz i get auto resolution switching and auto framerate switching (at 1080p 30Hz) when i start SPMC.
the videos from SPMC are played at 1080p with the appropriate framerate (and 1080p to 4K upscaling is by TV).
If i stop SPMC, the resolution and framerate come back to the default 2160p 60Hz.

I can post some images if they can be useful. ...... my english is not very good.